Why is concrete so expensive?
And what are the main costs involved?
In this article we will cover the major costs associated in getting concrete work done. We will look at why it can be expensive and ways to cut costs and hopefully save you money.
Here are some of the main costs broken down:
The Price of concrete
The most expensive ingredient in concrete is cement; other aggregates such as crushed rock and sand are relatively inexpensive in comparison. The price per cubic meter varies across Canada, but in Calgary is about $320 cm3.
While there are multiple factors that can increase the price of concrete let us look at a few such as the time of year, for example in the colder months accelerating chemicals are needed in the mix to speed up the process and adversely in the warmer months retarding chemicals are added to delay the concrete from setting. In colder climates like Canada that aggregates and water are heated up beforehand to prevent the concrete from freezing.
When ordering concrete trucks these are some of the factors that may increase costs:
• Small load charges (under a certain cm3)
• Environmental fees
• Distance to job may incur extra fuel charge
• How long it takes to unload the concrete, usually if it’s a bad access and takes a while a concrete pump will be used.
Access to site
Sometimes overlooked the access to site can be a key factor in higher costs. A bad access can make it difficult to get plant and equipment to site and require specialized equipment and increased manual labour costs. Placing the concrete may be an issue as well and require a concrete pump.
• Pump costs (usually between $400-600 for small to medium size jobs)
Excavations of existing concrete and earth removal
Removal of existing concrete and earth will generally incur extra costs as most concrete companies use sub-contractors to handle this. Costs can escalate quickly when existing concrete has excess steel reinforcement or if the ground has large rocks that require heavier rock breaking equipment to reach ideal depth.
• Prices will vary for excavation hire between operators ($50-$70 per hour) and depends on the amount of dirt to be moved and equipment needed
• Usually we charge $1 per sq. ft for basic earth removal and concrete work
Place and compact gravel
Typically most concrete requires a 4” sub-base for compacted gravel.
• Gravel costs - $55 per yard (again Calgary Alberta prices)
Labour & materials for formwork, rebar, and to place and finish concrete
Materials used in concrete slab prep work:
• Timber forms price varies depending size of timbers and no. required
• Steel rebar ($6-8 per 20’)
• Bar chairs to keep the rebar centred
Additional costs can add up when requiring:
•Plastic waterproof membrane ($70-$100 per roll)
•Styrofoam insulation is used ($1.50-$2.50 per sq. ft)
Labour costs can vary per concrete company but we aim for around:
• $2 per sq. ft for preparation/formwork strip/ site clean up
• $2 per sq. ft for concrete placement/finishing/site clean up
For more information and costs about:
• Common concrete slab sizes 20’ x 20’ (400 sq. ft) and above
• Common concrete slab sizes below 400 sq. ft
Footings
Usually for garages or on grade house slabs footings/ thickened edges are required for load bearing walls. Also getting concrete walls or planters will require footings.
Main costs incurred for footings are:
• Extra excavation labour time and potential excavator hire
• Extra concrete can be between $1-2 per sq. ft
• Having to order a smaller load and do a separate pour beforehand (usually for walls and planters) and incurring a small load charge.
Decorative boarders
Much like the footings boarders will typically by poured on a separate occasion beforehand. Thus increasing labour and material costs.
• Prices can range between $1-2 per sq. ft
Different concrete finishes and the costs involved
Plain grey concrete does not usually incur any extra costs unless its being power machine troweled. For smooth trowel, float, and broomed finishes are inclusive in the over all price. Some of the different types of finishes can be seen here.
• Machine troweled is around $0.40 - $0.80 per sq. ft this price also dependent on slab size
• Concrete sealer ranging from basic to more high end ($0.7-$2.50 per sq. ft)
• Control joints saw cut in post job ($0.50 per sq. ft)
Decorative concrete finishes:
Exposed aggregate finish
These are more expensive concrete per cm3. Additional labour and material costs as well
• Exposed aggregate concrete finish depending on the type of stone (an extra $100 - $400 per cm3)
• Special chemical spray that goes on the surface of slab after troweled ($50 - $200 size dependent)
• Labour costs for power washing the surface the next day with high pressure washer and slurry clean up ($200 - $400 size dependent)
• Concrete sealer ranging from basic to more high end ($0.7-$2.50 per sq. ft)
• Control joints saw cut in post job ($0.50 per sq. ft)
Stamped concrete pattern
Costs for having a stamped concrete design pressed into your concrete slab are
• Additional labour, as pressing the stamp templates into the concrete can be a slow process and require extra help.
• Stamp hire
• Chemical release to go in between the stamps and the concrete in either liquid or powder form
• Concrete sealer ranging from basic to more high end ($0.7-$2.50 per sq.ft)
Coloured concrete
Coloured concrete can also be added to the mix
• Depending on the colour type ($100 - $300 additional per cm3)
Saw cuts for contraction joints
Depending on the type of job or as per the clients requests post job saw cuts might be required
• Control joints saw cut in post job ($0.50 per sq.ft)
Concrete Stairs walls and planters
When getting stairs walls and planters installed the costs can vary allot. Most concrete contractors will have a minimum of say 8 stairs @ $400 per stair, 80 sq. ft of wall or 80 sq. ft for planters. Typically these costs can be reduced with multiple jobs done on the one site.
• Stairs main costs are mostly labour, as the excavations, gravel compaction, formwork, and rebar work is allot more intensive than traditional concrete flat work.
• Walls and planters as above labour costs will be the biggest factor in high costs
• Pre-poured footings will be required for walls and planters beforehand as well
Conclusion:
In conclusion there are many factors that can increase the cost of concrete work we’ve broken down a few of the main ones. Hopefully you can have a better idea of what’s involved in the concreting process and where allot of the costs are.
Even though the price of concrete and is quite high it will last you over 20 years and can make your home look amazing, from a decorative exposed aggregate driveway with stamped boarders to and fully landscaped backyard with hot tub pads, patios, sidewalks, driveways, extensions, garages, aprons, stairs, planters, and walls the possibilities are endless.
If you’re thinking about getting concrete work done and wanted to get an idea for costs involved we have a free online estimator that calculates allot of these factors in and can give you a close approximation. Free Concrete cost estimator.